The Earth
Astrologically Earth is rarely used in readings. Nevertheless, she's the central point from where we look up - she's our ground, physical rooting, anchor and that's an important part in our lives. How do we ground, how do we relate to nature and the direct energies we take up through our feet and food... maybe also the other "sensory" points - or senses.
To me Earth is also our "playground", where we materialize and manifest - in this sense a "womb" energy, what we "make her pregnant" with and let grow...
For more facts and details about Earth Astrology please scroll to the "relationship Geometry" and/or my general astrological approach read here: Axis and Cycles
Some Facts: We often think we know our home-planet but there are so many things not so obvious or "visible"/ perceivable in short periods of time.
Earth mean speed around the Sun is 29'783 km/second. The rotation speed around the own Polar axis at the equator is 1'674,38 km/second. As a comparison, the Solar System speed towards north (Solar Apex) around the Galactic Center is ca. 230 km/second or 828'000 km/hour and it takes us around 220 to 230 million years to go around once...
Earth is round, yes, but not exactly round and that might be contributing to some "phenomena"/ cycles that are detectable, yet still not fully understood...
There's the magnetic pole axis, which is "tilted" in perspective to "true north"/ecliptic - this axis of daily rotation/spin does hold two shift/wandering cycles like the precession of the equinoxes (the Ages) and that's also seen in Earth's cross (any planetary cross is seen in the planetary nodes / points in relation to the ecliptic (therefore Earth): scroll for details!!
Earth relationship-geometry
To get an idea about the astrological relationships or "co-operation" of planets, it's important not only to look at their own crosses or orbital points but also what kind of geometry is formed by their cycles.
Heliocentric sidereal planetary cycle Astrology.
It's of evolutionary relevance in my opinion.





Earth's own cycles - Science
There's the magnetic pole axis, which is "tilted" in perspective to "true north"/ecliptic - this axis of daily rotation/spin does hold two shift/wandering cycles:
The Precession of the Equinoxes (also called the "ages") an almost 26'000 year cycle, that means that to where (stars, constellation) the northpole points and is measured during the equinoxes when the Sun stands exactly at the celestial equator and causes day and night to be of equal length. It's a clockwise movement around the zodiac. - We can observe that as a change of "longitude".
Obliquity is the "wandering" of the tilt / pole axis in "up-down direction" - this causes the "angle" between true north and the rotation axis to increase or decrease - a ca. 41'000 year cycle. - We can observe that as change of "declination".

Important to know is the fact, that the Polar Axis and the equator are always in a square angle - forming a Cross.
Therefore, when the Polar Axis changes, so does the equator.
Earth rotates counter-clockwise (west to east) in 1 day. The precession of the equinoxes (March and September equinoxes / equatorial points) move roughly 1 degree in 72 years into the other direction.
The Pole Axis shifts and is often also called the "Tilt" - Obliquity changes from ca. 22.1 to 24,5 degrees. That's seen during the solstices, it's marked by the declination of the Sun's position as seen from Earth. We're now in a "decreasing" time of "tilt"/ obliquity since roughly the year 7420 BC. There was a small "strange action" in 2012 but we're back decreasing until the next change, that occurs roughly around the year 11970... (my own "year"/ time data research with an Astrology program)
Earth Eccentricity is the cycle of change of orbit-shape. From less elliptical shape to more elliptical and back - there are 2 cycles within the one: 1 ca. 100'000 years and the 2nd one 405'000 to 413'000 years.
At the moment Earth's Perihelion occurs roughly 2 weeks after the December Solstice and Aphelion 2 weeks after the June Solstice... The Solstice axis and Perihelion - Aphelion axis were last aligned (on the same day) in 1246 according to scientific calculations...
Both these two cycles are observable in Geological studies about the climatic periods of such cycles - they did trace these cycles back for like 200 millions years or so....
These 3 cycles are also known as the "Milankovitch cycles" - here a link with much more details about it including newer "discoveries":

(Picture/diagram not to scale!!)
Picture credits and References:
Iowa State University / Science Research Gate/ Science Direct/ Nasa and Milankovich Cycles on various sites and more.